Trafford, currently managing partner at Burghley Communications, replaces outgoing group communications director Shane O'Riordain.
In an email announcing his departure, O'Riordain, the ex-HBOS and Halifax comms head, said he would be 'taking a short break before seeking a new opportunity with another organisation'.
Trafford will assume responsibility for all of the group's external media relations, as well as internal communications.
A former group communications director and executive board member at ITV, she moved to City agency M:Communications in June 2008. She was also head of communications at Dow Jones and Cable & Wireless Europe.